Recall that a morphism of rings $R\to S$ is called (essentially) smooth if it is formally smooth and (essentially) finitely presented.
(Note: $R\to S$ is essentially finitely presented provided that $S$ is the localization of some finitely
presented $R$-algebra $T$ at some multiplicative system $A \subset T$, that is, $S=A^{-1}T$.)
In class, our professor said that working with smooth or essentially smooth morphisms yields an effectively equivalent theory. This motivates my question: Is there a general technique to lift results from the smooth case to the essentially smooth case?
For instance, if $R$ is reducedEdit: According to Mel, andevery essentially smooth morphism $R\to S$ isis a localization of a smooth morphism. However, then $S$this direction is reduced. It turns out thatmuch more involved than the same factother direction, which is true for essentially smooth mapsimmediate from the definitions. Is there a good way to "lift" Anyway, this resultwould be the answer to the more general case?question.